Many problems exist in rigging cables to secure barges together, including the following:
One man has difficulty handling cables to wrap in place about fittings on two adjacent barges and pull tight enough to fasten manually onto a tightening ratchet jack of limited span to hold multiple barges stiffly as a single unit. When eyes are in the cable ends for hooking about fittings, then the cable is not as flexible and becomes more awkward to place and wrap by kinking. Also, these eyes when handled on a free end of cable can foul or get caught on deck projections, etc. Furthermore, such eyes must be placed in a cable by hand splicing which requires special steel fids and clamps, or by a hydraulic press.
When two eyed ends are used, the cables need a certain length and the eyes are not usually the same size. If one end is bitter, then it must be clamped near the end by prior art winch type wedges and if there is excess cable length, it is then necessary to place and store extra non-used cable intermediate the ends such as by coiling on a winch in order to achieve the desired tightness.
There is no known prior art way to handle and use various length cables with both ends bitter for binding barges together. Even when one end is bitter and is clamped to a fitting or winch the cable must be bent so acutely in the prior art clamping devices that it is difficult to handle by one person. While some tolerances in cable lengths might be compensated for in using a selectable number of chain links for coupling a pelican hook on an adjustable ratchet jack to a cable eye, this process leaves excess chain and requires expensive eyes, chains and hooks permanently lodged in the rigging. Also, when tightened by the eye method this requires a tightener ratchet jack to become permanently a part of the rigging for each cable used, resulting in a large inventory of ratchets.
If one bitter end is wound on a winch, which is of itself expensive, an extra length of cable is necessary for securing several turns about the winch drum, thus increasing cable length and cost. The winches generally welded to barge decks, if inoperable, are difficult to service and replace, thus leaving equipment including cables with eyes, ratchet jack, chain links, no fail-safe secondary securing method other than by use of extra shackles, and pins.
Also in prior art rigging various deck hooks or fittings need be provided for cable eyes, ratchet moorings, etc. The only feasible prior art ways to keep the cables tight have been to leave the tightener ratchets and winches in place. Replacement is difficult and expensive.
Barges also have to be maneuvered into exact place and squared away for securing the cables about deck fittings in order to tighten the cables enough to provide a watergoing single unit. Even then the cable tautness that can be achieved by one person is not generally sufficient because of the limited tightening range, the handling of the loops and variously located fittings that need be processed. It has been difficult for a single man to handle some of the heavy rigging equipment alone, particularly if tugs need to move and square away the barges. Heretofore, it has been substantially impossible for a single person to exert forces sufficient to pull approximately squared away barges closer together into one stiff unit while tightening cables, even when using large and expensive winches, which furthermore need maintenance and have a tendency to foul cable on drums which must be carefully wound and layered from a single direction, thereby preventing effective use of tensile force over different pull angles. Most prior art rigging such as winches permit cables to be pulled only in a single direction with little variance in the pulling angle, and if reeled need be handled precisely in a winding pattern.
Also, it is desirable to remove as many deck obstacles and attachments as possible to reduce possibilities of injury in handling, manipulating and tightening cables.
Thus, the cost of equipment and rigging manpower is high in the prior art and the many problems presented have complicated the rigging and caused failures in rigging of barges together. Similar problems exist in other applications requiring cables held under tension between two fixtures for binding loads or securing objects together.
In the prior art, cables have been grasped and retained by clamping devices which tighten the grip on the cable as the pulling tension is increased, as shown in U.S. Pat. Nos. 453,378 to G. W. Rowley, June 2, 1891; 1,460,276 to J. A. Robertson, June 26, 1923; and 3,934,855 to W. W. Patterson et al., Jan. 27, 1976. Some of these clamps have the advantage of feeding a bitter cable end straight through the clamp and securing the clamp at any variable position therealong. They are also advantageous in permitting the cable to freely pass by movement in one direction and to be gripped by movement in the opposite direction.
Barges have been secured together conventionally by cables wrapped about deck fittings where each cable is secured by special tightener ratchets or winches permanently secured to the barge deck, as shown in U.S. Pat. Nos. 3,105,675 to W. L. Blackburn, Oct. 1, 1963; 3,785,324 to H. A. Guthans, Jan. 15, 1974; and 3,292,567 to W. L. Blackburn, Dec. 20, 1966.